The present invention generally relates to the flashing of chimneys and other hot gas vent conduit structures extending through roofs and, in a representatively illustrated embodiment thereof, more particularly provides novel roof flashing apparatus which permits a rubber boot to be utilized in the flashing of a metal chimney pipe extending through a roof opening without subjecting the rubber boot to an undesirably high temperature during firing of the fuel-fired heating apparatus with which the chimney pipe is operatively associated.
Rubber flashing boots are commonly used as flashing structures for sealing around non-heated pipes, such as plumbing fixture vent pipes, extending through roof openings. For a variety of reasons it would be desirable to utilize a rubber boot to flash around a heated pipe, such as a metal chimney pipe, extending through a roof opening. However, in the past this use of a rubber flashing boot has not been feasible since the necessary UL safety certification for this flashing application has not been obtainable due to the impermissibly high boot temperature levels resulting during the flow of hot combustion products through the chimney pipe. Additionally, chimney pipes flashed using rubber boots tend to fail to meet applicable wind loading test standards.
As can be seen, a need exists for apparatus and methods permitting the use of rubber flashing boots in through-roof chimney pipe applications. It is to this need that the present invention is directed.